Looking for GRP repair advice please

[Munky]

Really off topic, but wanted some input from our local experts please.

To try and make sense of the photo upload state, I was recently lucky enough to buy this 912. Well lucky enough until it arrived (internet purchase - I’m sure I’m not the first and won’t be the last…)

And I’m sorry to say that the Atom in the background has gone after 8 years (but an older Caterham still remains!!!)

[Munky]

The car is very much a 10 footer, if not 15.

Paint is a mess, slight undisclosed accident damage and I haven’t managed to get it to start yet.

It has a carbon fiber bonnet and the prior owner tried to fit spotlights to it. The first attempt was a failure (how do I know? Well the holes are still there) and the second time wasn’t a charm as the two lights are at different heights on the bonnet.

[Munky]

What is worse, is that there are a couple of cracks in the bonnet at the front where the bonnet curves down to meet the bumper, though there is a bonnet latch mounting point behind it to help strengthen it.

[Munky]

These are the cracks and the bonnet support.

[Munky]

I’m going to be painting the car, so I’m not worried about the carbon fiber ‘look’. Just wondering how best to fix it.
Is it possible to just use GRP?
Do I drill holes at the ends of the cracks and then dremel a V channel and then fill with layered mat and GRP resin?
What should I do about the holes?
Thanks for any advice!

[Munky]

Any thoughts?
Can I use GRP to fix a carbon fiber hood?
How should I fill the holes?
Thanks!

[Mister Towed]

I'd put a patch of fibreglass mat behind the holes then fill them with body filler once that's set. Sand it smooth and overpaint in the usual way. If the holes are bigger then I'd plug them with fibreglass filler after patching behind them then finish it with a smooth filler before painting. If it doesn't work then it's relatively easy to drill out and try something different.

[Munky]

Thanks Mr Towed.
I guess it’s about time I put my ‘big boy pants on’ and give it a try.
Nothing to lose. As it stands, I would have to replace it anyway.
Thank you.

[kon]

You might find a bag of loose glass chopped strands could be quite handy for filling the v-channels you grind out... depends what kinda matt you have already. chopped-strand matt would fill better than a woven one, for tight corners, and I believe the loose bags are even cheaper than CSM.

[Munky]

Thank you Kon for the great advice.
I’ll see what I can find on the internet for doing this.
Munky

[Lucky@LeMans]

Maybe try the carbon fibre filler that is available ? Perhaps find an original steel bonnet if you want to restore it .

[Munky]

Thanks Lucky.

I’ll have to look and see if I can find some locally.

I did buy a used hood for too good a price - too good in that it ended up being a mess when it arrived. And the weight!!! Oh my word, it weighed a damn ton - probably the filler in it…

Funnily enough, the seller didn’t manage to quite pick up on the issue areas in the photos he took…

The car isn’t ever going to be a concours restoration type car. It’s too far beaten up for that, so I decided to just enjoy it and have a bit of fun with it!

[Jaguartvr]

I would backfill the holes with GRP paste, if you use filler it will almost certainly crack and shrink. If you cover the holes with some polypropylene sheet or cut a bit out from a washing-up bowl, stick it to the top surface using duct tape. Then place an impregnated sheet of Chopped strand mat over thetop (back surface). Impregnate the CSM on a piece of wood with a small gloss roller, when fully impregnated place it on the panel and give it a good rollering. On this type of repair, you get better adhesion and finish than using a brush and stippling it on.
When dry remove the poly sheet and sand first and then use a small amount of filler, Dolphin Glaze is ideal. Before painting roller (or spray) a coat of ReFace over the repair to help prevent shrinkage at a later date.

[Munky]

Fantastic! Thank you.
I have this week off work, to if it’s not too hot in the garage, I’ll get on it!